Hydraulic lifting jack



Jur xe 15, 1926.

DORNENBURG HYDRAULIC LIFTING JACK Filed Nov. 1'7. 1925 m? I an: J I v 'I weight of the load thereon.

sure-cylinder; b the plunger of Patented June 15, 1926.

UNITED STATES PATENT OFFICE,

HEINRICH DfiRNENBURG, OF IElSrSEIbI', GERMANY, ASSIGNOR TO PRESSLUFT UNI) BEBIESELUNG, GESELLSCHAFT MIT BESCHRKNKTER HAFTUNG, OF GELSEN- KIRCHEN, GERMANY.

I HYDRAULIC LIFTING .mcx. f

Application filed November 17,

5 plunger therein, a container for the pressure-medium that can be forced into said cylinder by means of a pump actuated by a rocking hand-lever for lifting said plunger, while a pressure discharge-valve wlth projecting valve-rod is provided on said container and adapted when opened to permit of the pressure-medium flowing back from said pressure-cylinder into said container for again lowering the plunger under the According to the invention, the handle of said rocking lever is axially rotatable thereon and fitted with an integral cam, while said discharge-valve is with its projecting vvalve-rod so located beneath said cam that when rocking the lever with its cam upwardly directed it does not influence said discharge-valve and thus lifts the plunger while when rocking it with the cam down- 2 wardly directed the latter acts upon the valve-rod of the discharge-valve so as to open the latter.

The accompanying drawing illustrates the improved hydraulic lifting-jack: Fig. while Fig. 2 is'a cross-sectiontthrough the handle of the rocking lever on the line 2-'2 of Fig. 1.

The reference letters indicate: a the presthe latter; a the container for the pressure-medium with closable fitting opening i; d the pump hand-lever in conthereon; g the rocking and fulcrumed at h nection with said pum to said pressure-cylin er; f the axially rotatable handle of said hand-lever loosely 1925, Serial No. 69,669, and. in Germany November 10, 1924.

screwed upon the latter; 0 the integral cam on said handle; e the pressure dischargevalve on said container; and k the projecting valve-rod of said valve located beneath said cam.

As already explained, when rocking the hand-lever, g with the cam 0 upwardly directed, it acts to lift the plunger 1), while with the cam downwardly directed, the latter acts upon the projecting valve-rod k of the discharge-valve so as to allow a downward return of the plunger.

The advantage of the improved arrangement lies in the fact that by a simple axial rotation for about 180 of the handle of the lever g the latter can be easily, quickly and safely reversed from its position for lifting the jack plunger to that for lowering the same, without necessitating a removal and reinsertion of said lever or its handle.

What I claim, is:

The combination, in a hydraulic. liftingjack, with a pressure-cylinder, a plunger therein, a container for the pressure-medium, a pump to force the latter into sa'id cylinder, a rocking lever fulcrumedto said cylinder and adapted to operate said pump, and a pressure discharge-valve on said container comprising a projecting valve-rod; of an axially rotatable handle on said lever, .andan integral cam on said handle directly above -said valve, said cam when downwardly directed acting upon the valve-rod of said discharge-valve so as to open the latter while when upwardly directed it does not influence the valve during the rocking movement of the lever, substantially as set forth. a

In testimony whereof I have hereunto set my hand.

HEINRICH DORNENBURG. 

